Just another data point for the discussion:

The PSF is currently funding the effort to port pyOpenSSL to
Python 3.x and the port is nearly finished.

It may be worthwhile investigating adding the EVP interface
from evpy (with the ctypes bindings converted to real C wrappers)
to pyOpenSSL and then adding the pyOpenSSL package to the stdlib.

Note that going for other crypto libs than OpenSSL is currently
not an option, since those are not widely available on the OSes and
we cannot easily add crypto code itself to Python's stdlib due to the
issues with crypto import/export/use restrictions which would
limit the use of Python in various countries.